Bicycles (power-assisted bicycles) having a motor for providing additional driving force are widely known. A power-assisted bicycle is heavy due to the motor and a battery provided therein, and therefore, when the battery runs down, an amount of torque required to drive the power-assisted bicycle increases greatly. Hence, a user of the power-assisted bicycle must manage a state of charge of the battery appropriately to ensure that the battery does not run down on the go.
A power-assisted bicycle typically has a plurality of travel modes in which different degrees of assistance are provided. For example, a mode in which powerful assistance can be provided over a short travel distance, a mode in which the assist force is weaker but the travel distance is extended, and so on are often provided. The user of the power-assisted bicycle can adjust a travelable distance by switching the mode during travel so as to adjust the assist force.